I have followed the C-Series with great interest .
After having seen Dornier go bankrupt making the 728,
I think the C.300 will sell as hot cakes and at a lower price as Airbus uses their suppliers and the unit price comes down.
Otherwise there is nothing right now that You want to do with it with regards to hardware. I can imagine there is some with regards to training , SOP and operating philosophy that can be tweeked towards Airbus.
But if it aint broke why fix it. Just start selling it!